Pregabalin Could Ease Pain, Some Symptoms in IBS-D

LAS VEGAS -- Patients with irritable bowel syndrome (IBS) experienced reduced symptom-related pain when administered pregabalin (Lyrica) during a pilot study presented here Monday at the American College of Gastroenterology annual meeting.

Statistically significant findings for those administered the drug, as compared to placebo, included lower pain scores on the Bowel Symptom Scale (BSS) over the last four weeks of the 12-week study (26.1 with pregabalin vs 42 on placebo, P=0.008), and a lower average overall-BSS severity score (28.5 vs. 42.2, P=0.009), reported Yuri A. Saito, MD, of the Mayo Clinic in Rochester, Minn.

There also was a significant advantage for pregabalin in Diarrhea-BSS score (17 vs 32, P=0.049) and Bloating-BSS scores (29 vs 44, P=0.044) reported during weeks 9-12.

Results after the first 4 weeks of full-dose therapy -- when the study's primary outcome was evaluated -- were largely maintained through week 12, Saito said.

But the drug did not reduce constipation-related pain on the BSS, nor did it yield significant findings on the IBS Quality of Life scale, she reported.

A post-hoc analysis revealed a significant difference in abdominal pain scores as well. It was intended to account for a 2012 FDA guidance regarding IBS in controlled trials, Saito said, which were issued after the study was designed.

Side effects including constipation and upset stomach were more common in patients taking the drug, as were dizziness and blurred vision. Saito said those effects were expected. She noted that one patient in the pregabalin group died during the trial, which was judged to be unrelated to treatment.

Pregabalin, a GABA-ergic drug, is FDA-approved to treat fibromyalgia, certain other forms of chronic pain, and partial onset seizures, and is often used to treat generalized anxiety disorder and restless legs syndrome.

Saito and colleagues hypothesized that because many IBS patients have fibromyalgia and anxiety, the drug could also assist with IBS-related pain, which has limited treatment options. They aimed to collect preliminary data on how the drug affected GI symptoms in IBS patients.

With funding from pregabalin drugmaker Pfizer, they conducted a randomized, double-blind placebo-controlled, two-arm, parallel group trial of pregabalin in 85 patients with IBS (predominantly female, mean age 39.4). The drug was uptitrated to 225 mg twice daily during the first week of treatment and continued at that level for 12 weeks, with the dose tapered to zero during the final week. Participants kept daily diaries, and completed weekly self-administered questionnaires regarding symptoms, compliance and adverse events.

The study's sample size was "very small," Saito told MedPage Today, so additional research would need to scale it to multiple sites and replicated her team's findings. She added: "It comes down to are they (industry) interested" in funding new research? (Pfizer did not respond immediately to a request for comment.)

The sample was limited to English-speaking adults in the U.S. younger than 71 who were diagnosed with IBS and experienced at least one pain episode during a two-week screening period. The "severely" depressed were screened out, among others.

Researchers also collected information on the drug's impact on sleep, Saito told attendees at ACG in response to an audience member's question, but they have not yet examined that data. Saito promised to include such analyses in the study's eventual publication.

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